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The World's Most Powerful Diesel Engine
Posted by
kdawson
on Mon Jan 01, 2007 12:52 PM
from the zero-to-sixty-eventually dept.
from the zero-to-sixty-eventually dept.
trex279 writes "The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the world's most powerful diesel engine built to date. Each cylinder displaces a whopping 111,143 cubic inches (1,820 liters, equivalent to a cube 4 feet on a side) and produces 7,780 horsepower. The engine is about the size of a small building." The engine is intended for use in container ships.
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yeah but (Score:2, Funny)
Re:yeah but (Score:5, Funny)
Parent
Re:yeah but (Score:4, Informative)
Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.
I've seen this web site before, but probably not cited on
Parent
Re: (Score:2, Informative)
Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.
And the article also stated at the most efficient setting, the engine is >50% thermal efficient (more than 50% of energy is transferred to motion, rather than heat)
Of course, definitely not a consumer item!
Re:That kind of efficiency is impossible (Score:5, Insightful)
Conversion of heat into any other type of energy achieves it's maximum at 33% (the other 66% heats up the environment, according to the Laws of Thermodynamics).
No, the maximum efficiency for a heat engine [lightandmatter.com] is given by 1-T(low)/T(high) (absolute temperatures), which can be higher than 33%. If you can make T(high) high enough, and T(low) low enough, you can get 99% efficiency, or 99.9% efficiency, or whatever you like.
Arguably, these laws have not been proven, and they can't ever be proven. But they have been unchanged for quite some time now.
No, actually they have been proved, mathematically, within their realm of applicability, and to within the level of statistical certainty that's inherent in them (which is not an issue for a macroscopic device).
A breakthrough like this would not go unnoticed and thanks to my thermodynamics professor I would be the first one to hear about it (he's a nut about engines). So I think that part of the article is something someone tried to spike in to give the engine more of a wow-factor
No, the problem is just that you don't understand thermodynamics.
Parent
Re: (Score:3, Interesting)
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So the engine can go from 3300 C (the SSME combustion temperature) to about 50 C (nozzle exit is way below atmospheric pressure, so the boiling point of water is lower). Efficiency = 1 - 350/3600, >90%.
No, this is just the limit on the efficiency from the laws of thermodynamics. The actual efficiency is certainly much, much lower. Also, there's no way that the exhaust is at 50 C at the point when it loses contact with the nozzle, so the real thermodynamic limit is going to be way less than 90%.
As a
Re: (Score:3, Interesting)
Now, using that to accelarate am object may have useful or non-useful metrics. But it is hard to call that efficiency, though. (For example, accelarating a stationary object using a rocket engine takes more energy than picking the object up and throwing it. But we still don't try to throw the space shuttle into orbit for some reason...)
Re: (Score:3, Informative)
Suffice it to say, it is a very well established science, and all quite provable both theoretically and in practice.
Re: (Score:3, Interesting)
I know you're joking, but if you look at the cross-section in the article, you'll see that they wisely passed over the hemispherical head for a pent-roof head. They also made the engine incredibly undersquare - it has a 0.38 bore-to-stroke ratio. Diesels require very high compression ratios, and it's worth compromising a redneck's sense of aesthetics to get it.
Japanese, the late great manufacturing power? (Score:2)
Re:Japanese, the late great manufacturing power? (Score:5, Insightful)
Parent
Re: (Score:3, Insightful)
Uh, no... (Score:2)
Kinda puts a different spin on the whole thing, doesn't it?
Re: (Score:3, Funny)
Your numbers are all wrong (Score:3, Informative)
The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.
Some facts on the 14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm
Re: (Score:3, Interesting)
Moloch needs fuel... (Score:2)
Life imitating art? (More likely it's just an obvious design, but still.)
Re: (Score:2)
Just remember: (Score:3, Funny)
Yes, but... (Score:2, Funny)
(You thought I was going to ask something else, did you?)
Is more powerful more, or less, efficient? (Score:4, Interesting)
Re:Is more powerful more, or less, efficient? (Score:5, Informative)
I also note the article does NOT say 7780 HP, it says 108,920 horsepower at 102 rpm and more importantly, 5,608,312 lb/ft at 102rpm. I knew that 7780 HP was wrong because you can tweak the fire out of a 6 litre chevy diesel and get 1000 HP and 1500 to 2000 lb/ft torque.
Most diesels have a 3/2 to 2/1 ratio of torque over HP, but then most peak in the 2400-3800RPM area, not 102. That is an absurd amount of torque, which is what is needed to twist a prop, after all. At 1,556,002 cubic inches, this is 3.6 lb/ft of torque for every cubic inch, which is similar to the above example of a 6.0L engine (364 cu. in.) getting 1310.4 lb/ft. (stock would be closer to 650-850 lb/ft).
In otherwords, a pretty efficient engine.
Parent
Re: (Score:3, Informative)
Sure anonymous, mannerless fool and coward, they actually run on Diesel as their only fuel. http://www.shockwavejets.com/shockwave.cfm [shockwavejets.com]
The cylinder block yields less than 8K horsepower per cylinder, these jets 12K per turbine. Then mount 14 of them in a block and call it an engine, the jets will weight less and have more power.
er (Score:3, Interesting)
Re:er (Score:4, Interesting)
Really, nuclear engines are only seriosly problematic for airplanes (because of "roll-up"), and even that problem could be designed around. People just have an irrational fear of anything nuclear, and we relally need to get past that if we're going to care about CO2.
Parent
Comparable to 1904 steam engine technology (Score:4, Interesting)
In terms of mere size, this is comparable to steam engines of 1904 [nycsubway.org]. The Interborough Rapid Transit Company (the "IRT" to New Yorkers) built a plant in 1904 with a total output of 132,000 horsepower. The compound steam engines had bigger cylinders than this Diesel; 42 inches and 86 inches, compared to 38 inches for the new marine Diesel.
That was the high point of piston engines. Electrical generation was already converting from pistons to turbines, and even that 1904 IRT plant had a few smaller steam turbines.
There have been much more powerful marine powerplants than this, but they're usually multi-engine turbine systems. There's an annoying tendency in commercial shipping to have only one engine on large ships, which occasionally leads to accidents. [ntsb.gov]
Not even the most powerful engine... (Score:5, Informative)
Great fact-checking to start 2007 with...
Manufacturer's site has better info (Score:3, Informative)
copyright violation (Score:5, Interesting)
I am a self confessed Diesel nerd (Score:5, Informative)
Now look at Diesels. The smallest working Diesels are the little glow plug engines that are used to power model aircraft - actually semi-Diesels whose spiritual big daddy is the classical single cylinder 9 litre like the Bolinder. The biggest are these marine monsters with their two-metre throws. But they all are constrained by a few parameters that are broadly the same - the MEP and the mean piston speed.
At the normal running speed of about 100rpm the engine in the article is doing about 6-7 metres per second. At its normal cruising rpm of about 2000, my car engine is doing 33 revs per second * 2 * 90mm stroke - or 6 metres/sec. I haven't checked, but I fully expect that the working MEPs are within the same ballpark. It's nice to see that engines ranging from grammes to kilotonnes are constrained by a simple law based in metallurgy and tribology.
The other nice thing is, that with the exception of the tiny toy engines, all Diesels work more or less the same way, and the direction of change is by downwards replacement - technologies developed for large marine engines find their way ultimately into small engines. Modern auto engines with their electronic solenoid operated injection systems are basically a shrink of the marine technology of the 80s and 90s. Turbochargers also undergo shrinkage as their technology moves from marine to auto use, so we get the variable vane turbocharger turning up on entry level cars.
It would be wrong to force too many analogies, but there are resemblances between Diesel systems development and computer development that are perhaps more than skin deep.
Re:Pollution? (Score:5, Informative)
2 cycle engines are very common once you start moving up into the larger diesels. They're very different creatures, though they operate on similar principles. Diesel 2 cycles have separate lube oil in the crankcase, similar to 4-cyc gas engines. Thus, no continuous cloud of semi-burned lube oil coming out. Also, they're all (at least all that I've ever seen) direct injected, meaning fuel is delivered directly to the cylinder once the intake/exhaust ports are closed, thus no unburned fuel flows through.
Since diesel cylinder always get a full air charge, 2 cycle makes since - it's simple, and since you're only flowing air, you don't have the wasted fuel as in a gas 2cyc. As a by-product, you also get twice as much power from the same space as the equivalent 4 cycle at equal rpms. They do have more particulate problems, but these have been resolved well enough in the last few years to meet the new EPA Tier II diesel exhaust requirements.
vary the power output based on amount
Parent
Re: (Score:2)
One thing to bear in mind, is that these engines run at very low speed, so there is a lot of time for it to burn cleanly.
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Re: (Score:2, Informative)
Two-stroke gasoline engines use the slightly pressurized fresh air/fuel mixture to force the previous combustion event's exhaust out of the cylinder. Some mixing of the fuel and exhaust is bound to occur, potentially resulting in unburned fuel escaping in the exhaust flow.
In a diesel engine, air and fuel aren't mixed until the actual combustion event, so there's no chance (assuming the engine is tuned properly) of fuel escaping in the exhaust.
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No, and it is quite possible to design clean-running two-cycle gasoline engines.
O RLY? (Score:2)
Re: (Score:3, Informative)
I wish there were. The technology certainly exists. A clean-burning 2-stroke gasoline engine just needs 3 major things, direct injection (which already exists) a supercharger (which also exists), and port valves (which are also possible). No major car manufacturer seems interested in selling such an engine, though. Perhaps it's the R&D investment (totally new engine block, cylinder head, and piston top design), or just the fact
Re:Pollution? (Score:5, Insightful)
Are two stroke diesels as dirty running as two stroke gas engines?
No. The thing that makes gasoline two-stroke engines so dirty is the fact that they are generally valveless, combined with the fact that they burn their own lube oil, deliberately. The goal of a gasoline two-stroke engine is to reduce parts count and weight, which is why they are found on weed whackers, chainsaws, lawn mowers and snowmobiles.
A two-stroke diesel is generally not intended to reduce weight, or parts count, but size. They are not valveless, and they do not burn their lube oil. Once you get up into the 2000HP+ range, it's pretty much the only way to make the engine a manageable size.
This engine is about twice the power of the (also two stroke) engines found on rail locomotives. Those engines take up about 2/3 of the locomotive's length (the other 1/3 is generator) To get the same output in a 4-stroke engine would require an engine twice the physical size. Think about how physically large a locomotive is and contemplate that.
Parent
Re: (Score:3, Interesting)
A two-stroke diesel of the same output (the EMD 16-710) has twice the displacement (186 litres). This suggests that two-strokes aren't that space-efficient.
Re: (Score:3, Informative)
Re:Pollution? (Score:4, Informative)
Two stroke gasoline engines tend to pollute a lot for two reasons:
some
1. They use the incoming fuel/air mixture to push out the exhaust and inevitably some of the unburned fuel goes straight out the exhaust.
2. Most of them use the crankcase to pressurize the incoming fuel/air mixture. This necessitates adding oil to the incoming charge to lubricate the crank and piston.
These aren't issues for diesels because the fuel is injected directly to the combustion chamber after the intake and exhaust ports have closed, and the incoming charge is pressurized by a supercharger rather than the crankcase.
Parent
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The author added something about it being able to play Ogg Vorbis files.
Re: (Score:3, Informative)
Would it run on biodiesel?
With the usual cuts in output, most likely, yes. (You take a really small cut in engine output when running it on biodiesel, something like 10% or so, but I don't have the figure right in front of me). It's still a diesel engine, just a hell of a lot bigger.
Re: (Score:3, Interesting)
It wouldn't be useful from a commercial perspective of course. From a cultural one, it could be incredible. You could have an entire culture of nomads living on the ocean, never needing to make port. That whole international waters thing could be good too - casino ships?
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What's wrong with the summary? (Score:3, Insightful)
Large engines often have multiple cylinder configurations so the customer can choose how many they want based on their need, so it's often better to list the power per cylinder than for the entire engine.
Re: (Score:3, Funny)
No but it will run over linux quite easily...